DNAs from 253 fresh human tumors of 38 different types were hybridized with 17 different oncogene probes. The analysis demonstrated unique associations between amplification of specific oncogenes and specific types of tumors. In a large number of cases it was determined that amplified oncogenes occurred in 10 to 20% of tumors with the following specific associations: c-myc in adenocarcinomas, squamous carcinomas and sarcomas but not hematologic malignancies; c-erbB2 in adenocarcinomas, particularly breast cancers; c-erbB1 in squamous carcinomas; N-myc in neuroblastomas. A small number of cases suggested other specific associations: amplified c-myb in breast cancers; amplified c-ras-Ha and c-ras-Ki in ovarian carcinomas. In addition, there was a correlation between amplification of c-myc and the clinical stage of adenocarcinomas, and amplification of c-erbB2 and the clinical stage and lymph node involvement of breast cancers.